1.4401 vs 1.4462 Duplex Stainless Steel Comparison

What Are 1.4401 and 1.4462?

1.4401 (X5CrNiMo17-12-2) is the molybdenum-bearing austenitic grade known commercially as AISI 316. It has roughly 17% chromium, 12% nickel and 2 - 2.5% molybdenum, and it is the workhorse of chemical, pharmaceutical, food and marine fabrication where chloride levels are moderate.

1.4462 is a duplex stainless steel with a mixed austenitic and ferritic structure, about 22% chromium, 5% nickel, 3% molybdenum and a deliberate nitrogen addition. It is supplied as the grade commonly called 2205 and matches the UNS numbers S31803 and S32205, which are ordered as ASTM A182 F51 and F60 for forged bar respectively. Duplex grades were developed for pulp and paper service in the 1930s and offer roughly twice the yield strength of 316 together with a substantial gain in chloride resistance.

Equivalent Grades

Standard	1.4401	1.4462
EN designation	X5CrNiMo17-12-2	X2CrNiMoN22-5-3
AISI / common name	316	2205 duplex
UNS	S31600	S31803 and S32205
ASTM product spec	A240, A276, A312	A240, A276, A182 F51 or F60

The two UNS numbers for duplex matter in practice. S32205 tightens the chromium, molybdenum and nitrogen ranges compared with the older S31803, which raises the pitting resistance of the delivered material, so the mechanical and corrosion data in a duplex quotation should always be read against the UNS number and the product specification actually named on the order.

Chemical Composition Comparison

Element	1.4401 (316)	1.4462 (2205)
Carbon	0.07% max	0.03% max
Chromium	16.5 - 18.5%	21.0 - 23.0%
Nickel	10.0 - 13.0%	4.5 - 6.5%
Molybdenum	2.00 - 2.50%	2.50 - 3.50%
Nitrogen	0.10% max, residual only	0.10 - 0.22%, deliberate addition
Manganese	2.00% max	2.00% max
Silicon	1.00% max	1.00% max
Phosphorus	0.045% max	0.035% max
Sulphur	0.030% max	0.015% max

Nickel is controlled as a residual in neither grade, but its role is completely different. In 1.4401 the high nickel content is what keeps the structure fully austenitic. In 1.4462 nickel is balanced against chromium, molybdenum and nitrogen so that the ferrite and austenite fractions each settle at roughly 50%, a balance that gives duplex steel its combination of strength and stress corrosion resistance.

Mechanical Properties at Room Temperature

Property	1.4401 (316)	1.4462 (2205)
Tensile strength Rm	500 - 700 MPa	620 - 880 MPa
Yield strength Rp0.2	200 MPa min	450 MPa min
Elongation A5	40% min	25% min
Hardness	215 HB max	290 HB max
Modulus of elasticity	about 193 GPa	about 200 GPa

The yield strength advantage of duplex steel is the single most useful difference for designers, because it allows wall thickness, weight and sometimes cost to be reduced in pressure retaining components. The trade-off is lower elongation and a narrower window of acceptable fabrication practice.

Corrosion Resistance, Fabrication and Applications

The pitting resistance of an austenitic or duplex stainless steel is commonly ranked with the pitting resistance equivalent number, calculated as PREN = Cr + 3.3 x Mo + 16 x N. Using the specified mid-range compositions, 1.4401 reaches roughly 24 - 26 while 1.4462 reaches about 34 - 36, which explains why duplex steel withstands chlorides far better and is essentially immune to chloride stress corrosion cracking at normal service temperatures where 316 can crack.

Fabrication demands differ too. 1.4401 is easy to cold form, easy to machine and very tolerant in welding with TIG, MIG or manual metal arc processes; post-weld cleaning such as pickling or brushing restores corrosion resistance. 1.4462 is harder to form because of its higher strength, work hardens readily during cold forming, and needs controlled heat input during welding together with a ferrite balance check so that the cast structure does not lean too far toward ferrite and lose toughness. Hot forming must stay within the approved temperature range, and annealing of duplex steel requires fast cooling to avoid sigma phase.

Application area	Preferred grade	Reason
Food and beverage tanks, pipelines, architectural rails	1.4401	Good general corrosion resistance with easy fabrication
Chemical and wastewater equipment, moderate chloride duty	1.4401	Balanced cost and corrosion performance
Seawater piping, desalination and platform structures	1.4462	High chloride pitting and stress corrosion resistance
Reactors, heat exchangers and pulp or paper process stages	1.4462	Strength plus resistance to aggressive media

FAQ

Q: What is the equivalent of 1.4401 stainless steel?
1.4401 is equivalent to AISI 316 and UNS S31600, and it is written X5CrNiMo17-12-2 in EN specifications.

Q: What is the equivalent of 1.4462?
1.4462 is the duplex grade commonly called 2205, corresponding to UNS S31803 and UNS S32205 and to ASTM A182 F51 and F60 for forged bar.

Q: Is 1.4462 stronger than 1.4401?
Yes. Duplex 1.4462 has a minimum yield strength of about 450 MPa against 200 MPa for 1.4401, roughly double the strength at the same temperature.

Q: Which grade resists chlorides better?
1.4462. Its PREN of about 34 - 36 is well above the 24 - 26 of 1.4401, and it resists chloride pitting, crevice corrosion and stress corrosion cracking far better.

Q: Can 1.4462 be welded like 316?
It can be welded, but with tighter control of heat input, interpass temperature and shielding, and with verification of the ferrite to austenite balance in the joint.

Q: Is 1.4401 or 1.4462 more economical?
1.4401 costs less per kilogram and is easier to fabricate, so it stays the better choice where corrosion demand is moderate. Duplex steel often wins on total cost in high pressure or highly corrosive duty because less material is needed.